1. Technical Field
The present disclosure relates to a technique of, in a lensless microscope, generating an image of an object in a virtual in-focus plane based on a plurality of captured images.
2. Description of the Related Art
In a wide variety of fields in which cells for treatment are produced, cells are used in evaluating effects of medicines, or cultured cells are used in medical treatment or industries, there is a need for continuously observing cells in culture without staining them. However, many cells are almost colorless and transparent, and thus it is difficult to recognize a three-dimensional structure of such a cell observed by an optical microscope using transmitted light.
In a technique disclosed in Japanese Unexamined Patent Application Publication No. 2013-101512, to evaluate a cross-sectional shape of a cell, an in-focus image (a pseudo cross section image) is generated in a plane not parallel to an objective lens from many images captured in focal planes that are parallel to the objective leans and that have different focal-point heights from an object (that is, the in-focus image is generated from many images captured while changing the position of the in-focus plane in a direction of height of the object).
Continuous observation of a cell in culture is performed in a limited space called an incubator keep a high-humidity environment necessary to culture the cell. For use in observation in such a high-humidity limited space, U.S. Patent Application Publication No. 2014/0133702 discloses a lensless microscope capable of observing a small cell without using a lens. In this technique, a plurality of images are captured while changing the position from which irradiation light is emitted, and the images are superimposed thereby achieving improved resolution. This technique is called ptychography.